Distributed Bragg Reflectors (DBRs) are used is photodetectors, lasers, solar cells, and other optical sensors. DBRs include multiple layers of alternating materials that have different refractive indices, the thickness of which typically varies from several to several tens of micrometers, depending on the materials. There are several parameters that determine the performance of DBRs, such as refractive index contrast, the roughness of the top surface, and the condition of the interfaces between materials. Epitaxial growth makes it possible to fabricate group III-V semiconductor-based photonic devices, including DBRs, on group III-V material substrates. However, these DBRs typically require many (e.g., >20) layers of material and need to be quite thick (e.g. >10 μm thick) to achieve greater than 90% reflectivity. DBRs constructed from silicon and silicon oxide layers, on the other hand, have a high refractive index contrast, so that they provide high reflection with a more compact structure, compared to DBRs constructed from group III-V materials. DBRs based on pairs of silicon and silicon dioxide (Si/SiO2 DBRs) have been fabricated using chemical vapor deposition (CVD) to deposit polycrystalline (poly-) Si as the silicon layers. (J. C. Bean, J. Qi, C. L. Schow, R. Li, H. Nie, J. Schaub, and J. C. Campbell, “High-speed polysilicon resonant-cavity photodiode with SiO2/Si Bragg reflectors,” Photonics Technology Letters, IEEE 9, 806-808 (1997).) However, the roughness of the layer surfaces in such DBRs increases with increasing number of layers. (S. Akiyama, F. J. Grawert, J. Liu, K. Wada, G. K. Celler, L. C. Kimerling, and F. X. Kaertner, “Fabrication of highly reflecting epitaxy-ready Si—SiO2 Bragg reflectors,” Photonics Technology Letters, IEEE 17, 1456-1458 (2005).) In addition, structural imperfections in the CVD-grown materials, such as local variations in the refractive index, grain boundaries, stacking faults, dislocations, crystallographic twinning, mosaic misorientation, and localized defects, degraded the overall DBR performance by increasing undesirable scattering. (G. Harbeke, “Optical properties of polycrystalline silicon films,” in Polycrystalline Semiconductors (Springer, 1985), pp. 156-169.) To solve the issues related to interface roughness and post-epitaxial growth, Si/SiO2 DBRs were made using multiple oxygen implantations into a single-crystalline Si substrate at different depths. (Y. Ishikawa, N. Shibata, and S. Fukatsu, “Epitaxy-ready Si/SiO2 Bragg reflectors by multiple separation-by-implanted-oxygen,” Appl. Phys. Lett. 69, 3881-3883 (1996).) However, limitations on the choice of Si and SiO2 layer thicknesses prevent this method from achieving ideal design parameters since the interface morphology is dependent on the thickness of both layers. A DBR having a single-crystalline top Si layer and polycrystalline lower Si layers has been fabricated using CVD on top of a silicon-on-insulator (SOI) wafer, followed by etching back the entire Si substrate layer and buried oxide layer to expose the top Si layer. (S. Akiyama, F. J. Grawert, J. Liu, K. Wada, G. K. Celler, L. C. Kimerling, and F. X. Kaertner, “Fabrication of highly reflecting epitaxy-ready Si—SiO2 Bragg reflectors,” Photonics Technology Letters, IEEE 17, 1456-1458 (2005).) This DBR had 7 pairs of Si/SiO2. To reduce the total DBR thickness, DBRs made using a Smart-Cut process have been proposed to insert a single-crystalline Si in each layer pair. (M. K. Emsley, O. Dosunmu, and M. S. Unlu, “Silicon substrates with buried distributed Bragg reflectors for resonant cavity-enhanced optoelectronics,” Selected Topics in Quantum Electronics, IEEE Journal of 8, 948-955 (2002).) In addition, DBRs fabricated with transferred single-crystalline silicon layers and amorphous Spin-on-Glass (SOG) silicon oxide (SiOx) layers have been disclosed. (W. Peng, M. M. Roberts, E. P. Nordberg, F. S. Flack, P. E. Colavita, R. J. Hamers, D. E. Savage, M. G. Lagally, and M. A. Eriksson, “Single-crystal silicon/silicon dioxide multilayer heterostructures based on nanomembrane transfer,” Appl. Phys. Lett. 90, -(2007).) However, it is difficult to precisely control the thickness of an SOG oxide layer and the non-uniform SOG oxide surface left voids at the Si/SiOx interface after the transfer of the silicon layer. Such voids may affect the DBR performance and the bonding strength between the two layers.